The invention relates to a flow washer assembly and, more particularly, to a flow washer assembly that regulates flow of fluid with a dynamically changing orifice diameter to keep the flow rate of fluid constant within a given pressure range. The assembly endeavors to eliminate a spike in flow rate that occurs with conventional flow washer assemblies.
A common problem with this type of flow control device is a “spike” in the flow rate as the inlet pressure is increased from zero psi to the operating range. As the inlet pressure increases, so does the flow rate through the device, until such time as the inlet pressure is great enough to cause a deflection of the elastomeric washer, which in turn causes a reduction in washer orifice diameter, resulting in a flow rate reduction. The flow spike occurs at the point where the pressure is great enough to cause an “overflow” or “spike” condition yet not great enough to cause a deflection in the elastomeric washer.
In an agricultural sprinkler application, this “spike” in the flow rate can create a significant problem. When the flow “spike” in the individual sprinklers is multiplied by the number of sprinklers in a given system, the amount of increased water flow is substantial. The water pump that pressurizes the system is usually sized so that it supplies just enough water flow to pressurize a given number of sprinklers at a certain maximum flow rate. When all the sprinklers in a system experience a “spike” in flow rate at the same time, the water pump cannot produce enough flow to adequately pressurize the system. When this situation occurs, the flow control devices at each individual sprinkler will never get enough pressure to regulate the flow rate. As a consequence, the system will never get to its optimal operating pressure, and the individual sprinklers will not function as designed.